float_filter.h

// Pithesiser - a software synthesiser for Raspberry Pi
// Copyright (C) 2015 Nicholas Tuckett
// 
// This program is free software: you can redistribute it and/or modify
// it under the terms of the GNU General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
// 
// This program is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
// GNU General Public License for more details.
// 
// You should have received a copy of the GNU General Public License
// along with this program.  If not, see <http://www.gnu.org/licenses/>.

/*
 * filter_float.h
 *
 *  Created on: 15 Feb 2013
 *      Author: ntuckett
 */

#ifndef FILTER_FLOAT_H_
#define FILTER_FLOAT_H_

typedef struct float_filter_definition_t
{
	int		type;
	float	frequency;
	float	gain;
	float q;
} float_filter_definition_t;

typedef struct float_filter_state_t
{
	float input_coeff[3];
	float output_coeff[2];
	float history[2];
	float output[2];
} float_filter_state_t;

typedef struct float_filter_t
{
	float_filter_definition_t	definition;
	float_filter_state_t		state;
} float_filter_t;

extern void float_filter_init(float_filter_t *filter);
extern void float_filter_update(float_filter_t *filter);
extern void float_filter_apply(float_filter_t *filter, float *sample_data, int sample_count);

#endif /* FILTER_FLOAT_H_ */